If the cake needs to be on display for over five hours I use Frostin Pride or Bettercreme in place of the whipping cream. I use 2 cups Frostin Pride and one small box of instant pudding. If making a large batch I will take 3 cups of Frostin Pride and whip on medium speed to create volume. Then I take one cup of Frostin Pride and mix two small boxes of instant pudding in a bowl. Once your Frostin Pride has doubled in size I add the pudding mixture and whip until stiff peaks start to form. This filling can stay out at room temp for up to five days. Stays nice and firm no bulging and I don't have to worry about how long the cake will be on display. I used this filling in the cake below. Sorry the pick is so dark they turned the lights off when we were taking pictures. They promised me a professional shot I'm still waiting.
